Device for illuminating thermometers and similar instruments.



M. B. MUELLER.

DEVICE FOR ILLUMINATING THERMOMETERS AND SIMILAR INSTRUMENTS. APPLIOATIOIf FILED JAN.30, 1912.

1 035 5; I Patented July 14,1914.

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Specification of Letters-Patent.

Patented Julyld, i914.

Application filed January 80, 1919. SeriaI No. 674,306.

. T all whom it may concern:

Be it known that I, MAX E. Momma, a citizen of the United States, and a resident of the borough of Brooklyn, in the county 5 of Kings and State of New York, have invented certain new and useful Improvements in Devices for Illuminating Thermometers and Similar Instruments, of which the following is a specification.

The invention relates to devices for illuminating thermometers and similar instruments, and its objects are, among others, to provide a device of this character of simple inex ensive and compact construction, which wi l effectively illuminate the instrument and which may be applied to the said instrument without material change in its construction or form, and which will illuminate it in such a manner that it will be plainly visible to the eye and quickly read or observed. The improvements consist of the construction, combination and arrangement hereinafter described and claimed, and illustrated in the accompanying-drawings.

In the said drawings Figure 1 is a front view of a thermometer, wlth an illuminating device embodying the improvements applied thereto. Fig. 2 is a vertical section on the line 2-2 of Fig. 1. Fig. 3 is a view similar to Fig. 2 of a modification.

Devices of this character are useful in many ways and may be employed in incubators and other places where the thermometer is placed in an obscure or dark location, 'as well as in sick rooms where illumination isnot desired, in which latter case-as well as in othersthe illuminating device which is the subject of'this invention may be used in connection with an ordinary thermometer or a clinical thermometer. In the drawings A is the plate of the thermometer, provided with the usual graduations and signs, and B is the ordinary glass tube of the thermometer secured to the plate by means of collars A and having a mercury bulb B at its bottom, from which the mercury rises in a column in the tube with the temperature. The thermometer shown in the drawings, for illustration, is one ordinarily used in incubators, and is, therefore, provided with graduations indicating-temperatures'from 85 to 115 only. C represents a casing of substantially semi-cylindrical form secured to the upper within the bore of the casing part of the plate A, and adapted 'to receive a plug D inclosing the butt and socket of an electric light bulb E, from which the wires E extend to a suitable source of electric current. The plug D is preferably made of wood, fiber or some other slightly compressible material so as to fit snugly 'C and exclude all light, and. at the same time support the hgli't firmly and securely. A small set-screw D extends through the casing and bears against this plug D, so as to prevent it from movlng under any unusual strain.

The forwardend C ofthe casing is of approximately funnel shape, and has at its lower end an opening provided with a packing C Through this op ning the upper end of the thermometer tube extends to close proximity to the electric lightbulb so that the rays of the light pass down directly through the glass of the said tube and illuminate the same so asto make it present a striking contrast to the background and to the column of mercury within it. The interior of the casing C is of reflective material, and this may be provided by simply polishing the interior of the metal of which the casing is composed.

The result of the construction and arrangement describedis that the light of the bulb is confined in every direction, except the direction of the column of mercury and is projected down through the tube surcolumn in such manner that rounding that direction, but is it does notradiate in any confined to the said tube. V

In the modification shown in Fig. 3 the casing C corresponding to the casing C is not attached to the thermometer plate A, and is preferably cylindrical in form with a contracted lower ortion C and an opening at the bottom t ereof, provided with a packing ring C through'which the upper end of a clinlcal thermometer may be passed to proximity to the electric bulb.

When desired, the casing may be provided with a plurality of openings to receive two or more thermometers or similar instruments, as for instance a thermometer and hygrometer.

The thermometer tube B is' provided with a reflective back B which may consist of a coat of white enamel or other light-reflecting substance, to form a background for the mercury column therein, and the rays of li ht projected through the upper end of the tu will illumine this background as they pass downward through the said tube.

The object of the illuminating device constructed and arranged as here n described, is not to throw a light on .the column of mercury or other substance in the lass tube, but to so illumine the tube itself that the said column will stand out in relief against the illuminated glass. It is, therefore, necessary that the glass of the tube shall have considerablc thickness, and that the light shall be projected directly against its upper end and in a direction parallel with the tube.

The words opaqueliquid in the claims embrace mercury and the other expansible fluids used in thermometers and similar instruments, which fluids may be imperfectly opaque but sulficiently non-translucent to intercept the rays of light and present a marked contrast to the illumined surroundin tube.

%Vhat I claim as new isi 1. -In a device of the character described, the combination of a casing, an illuminatin device therein, said casing. being pro- .vi ed with an opening,a tube of light-transmitting material fitting the said opening adapted to project therethrough into the said casing and into proximity to the said illuminating device, and being .partially filled with an opaque liquid the sald casing tapering toward the said tube and having a re ective interior, the construction and ar-- rangement being such that the light of the illuminating device is projected longitudinally of the tube so as to be intercepted by the opaque substance in the bore ofthe tube and to, pass beyond the same to illuminate the material of the tube below the upper surface of the opaque substance.

2. In a. device of the character described, the combination of a casing, an illuminatin device therein, said casingbeing provided with an o ening, a tube of light-transmittingmaterlal fitting the said opening adapted to project therethrough into the said casin and into the field of direct radiation-of sald illuminating device, and being partially filled with an opaque liquid, the construction and arrangement being such that the light of the illuminating device is projected longitudinally of the tube so as to be intercepted by the opaque substance in the bore of the tube and to pass beyond the same to illuminate the material of the tube below the upper surface of the opaque substance.

Witness my hand this 18th day of January, 1912, at the city of New York, in the county and State of New. York.

v MAX E. MOELLER.

Witnesses:

MARY LEWIS, ALAN C. MGDONNELL. 

